The present invention is directed to a drug delivery system that is subcutaneously-implanted for repeated intravenous, intra-arterial or intraperitoneal injections or infusions into the human bloodstream of drugs, antibiotics, parenteral products, blood, therapeutic agents, and the like. The system may also be used for the withdrawal of blood samples from the patient. The subcutaneously-implanted delivery system allows for up to 2000 needle penetrations, with a non-coring 22-gauge needle, to the artery or vein, without having to access the artery or vein directly, thereby considerably increasing patient comfort, as well as eliminating the hitherto high risk of infection and thrombosis due to repeated venipuncture. Furthermore, extravasation of some drugs is also eliminated, as well as the time expended by medical personnel in the search for a suitable vein to deliver drugs, or the like, to the patient. The subcutaneously-implanted delivery system also allows for regionalized therapy, and the system does not interfere with the patient's normal routine, since there are no exterior components which could be damaged through daily activities of the patient.
When the subcutaneously-implanted delivery system is to be used as an intravenous system, the system's catheter is typically inserted into the superior vena cava, or right atrium, through the subclavian vein or internal jugular vein, with the portal, or main housing of the system, placed over the patient's third or fourth rib. For intraarterial delivery, the catheter is usually inserted into the hepatic artery and the portal, or main, housing placed over the patient's lower ribs. For intraperitoneal delivery, the catheter is inserted into the peritoneal cavity via a small incision on either side of the umbilicus. The catheter tip is then placed to the right or left of the pelvic gutter prerectally. In this instance, the portal housing of the system is also usually implanted over the lower ribs. In each case, the portal housing is implanted and sutured to the muscle fascia at the appropriate site.
The delivery system includes the portal housing, which also includes a self-sealing septum through which a non-coring needle is inserted to a depth which penetrates the septum and into the reservoir chamber of the portal housing, which is in fluid cooperation with an end of the catheter communicating with the reservoir chamber. The catheter is connected at its other end to the particular and appropriately-chosen vein or artery. For injection or infusion, the drug or fluid being administered flows from the needle through the reservoir chamber of the portal housing, and then through the catheter directly into the vein, artery or peritoneal cavity. The non-coring needle is provided with a very sharp deflected point, thus preventing coring or removal of a portion of the septum upon penetration and removal, thus allowing for repeated injections with as many as 2,000 punctures using a 22-gauge needle. The system is, therefore, especially suitable for therapy involving numerous administrations of a multitude of drugs, such as in chemotherapy regimens. The fluids that may be transported through the portal housing, and through the catheter to the bloodstream, are drugs such as antineoplastics, antibiotics, whole blood products, red blood cell products, any many other fluids. At the same time, of course, blood samples may be taken by the same process. Studies have shown that there is considerably fewer instances of infection, sepsis, and catheter occlusion since only the septum is accessed, and the vein or artery is accessed only once.
Examples of prior art subcutaneously-implanted delivery systems are: U.S. Pat. Nos. 4,190,040; 4,405,305; 4,464,178; and 4,569,675. In all prior art implanted delivery systems, it is essential that the septum be force-fitted into the portal or main housing such that there is no likelihood of it coming loose and allowing air into the system. It is also essential that the silicone septum, mounted in the portal housing, be compressed in order to allow for the maximum number of punctures of the septum, with the preferred being over 2,000. Also, conventional systems require extremely close tolerances because the stainless steel parts are press-fitted, or are assembled in three pieces with mating thread connections. In these prior art products, the percentage of rejects due to improper sealing of the interior reservoir chamber is unacceptably large. Further, these prior art products can, with time, pose serious problems with leakage from the interior reservoir chamber connecting the septum to the catheter. In addition, the number of critical tolerances in prior art products are considerable because of the number of parts used and the surface areas involved. For these reasons, the present invention is directed to minimizing tolerance requirements and the number of parts requiring such close tolerances, and for reducing the number of parts, per se, in the portal housing as well as the structure for compressing the septum in the interior of the housing above the reservoir chamber, all of which lead to considerable ease in manufacture, compared to prior art techniques and products, as well as enhanced and improved efficiency of the product itself. While the product of the present invention, as used in its implanted state, is used substantially similar to prior art products, it offers a safer, more easily handled, and more comfortable subcutaneously-implanted fluid delivery system, whether for intravenous, intra-arterial or interperitoneal delivery.